[Linux-cluster] fcntl locking lockup (dlm 1.07, GFS 6.1.5, kernel 2.6.9-67.EL)

[Kevin Anderson]

On Tue, 2008-01-08 at 22:39 -0500, Charlie Brady wrote:
> On Tue, 8 Jan 2008, Gordan Bobic wrote:
> 
> > Charlie Brady wrote:
> > > On Fri, 4 Jan 2008, Charlie Brady wrote:
> > > 
> > >> I'm helping a colleague to collect information on an application lockup 
> > >> problem on a two-node DLM/GFS cluster, with GFS on a shared SCSI array.
> > >>
> > >> I'd appreciate advice as to what information to collect next.
> > > 
> > > Nobody have any advice?
> > 
> > Shared SCSI as in iSCSI SAN or as in a shared SCSI bus with two machines 
> > connected via a SCSI cable?
> 
> The latter. I don't have the details immediately at hand, but it's all HP 
> gear. A pair of DL380s with an external SCSI array (MSAxx), IIRC.
> 
 If it is a MSA20, MSA30 or MSA500 - they won't work with GFS.  Shared
SCSI bus isn't really shared, accesses lock the bus such that when one
node accesses the storage the other node is locked out.  GFS requires
the ability to do shared concurrent access to the storage devices.  This
probably explains the hangs you were seeing.  So, either get an iSCSI or
fibre channel storage array, or go strictly with a failover storage
architecture, such that only one node has the filesystem mounted at any
one time.  In that case, you don't need gfs anymore, just cluster suite
to manage the failover.

Kevin

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